LINQ To SQL in Compact Framework

Question

Im on to design my Data Access for a new solution i create. That solution though contains Compact Framework Device Application and libraries besides Desktop. All .NET 3.5. Desktop will handle all Data Access basically. I need the Data Objects to have in CF too, Desktop will communicate with SQL and then with Mobile and give the appropriate data...

I love LINQ, and more i love LINQ 2 SQL. There is a lot of hype out there and i don't buy internal Microsoft politics about recommending EF. For now EF is too heavy and too complex for someone to choose it besides it still evolving and EF 4 will have major changes when it comes in a few months. But i cant wait for months to create a project as every developer in here, i want something now! After that said i want to use LINQ 2 SQL, my problem is that i cant just copy the generated dbml and use the generated classes. I don't need the DataContext cause i don't intend to use CRUD or any operations on a database with the Mobile App. i Just want the Objects. Anyone ever came in a situation like this? The whole point is not to write all classes representing the tables by hand. Cause i need them for further LINQ to Objects manipulation.

Basically an ORM supporting CF would do the job! But i don't know any incompatibilities i would meet.

Answer 1

L2S works great with the compact framework. You can't use the drag-and-drop designer, though. You'll need to run SQLMetal.exe yourself to generate the classes for you.

SQLMetal.exe: http://msdn.microsoft.com/en-us/library/bb386987.aspx

Example with Northwind compact: http://blogs.msdn.com/sqlservercompact/archive/2007/08/21/linq-with-sql-server-compact-a-ka-dlinq-over-sql-ce.aspx

Another example, with lots of pictures: http://pietschsoft.com/post/2009/01/Using-LINQ-to-SQL-with-SQL-Server-Compact-Edition.aspx

Answer 2

You could use DevExpress persistent objects (XPO) on compact framework. I have used it before but found it to be somewhat slow for my purpose (data collection application).

The reason that you cannot find much of this on the compact framework is that speed is usually so important for device apps, that data access code is usually done manually.

I don't know if you can create objects from an already existing database with XPO.

Answer 3

I've been able to modify SubSonic 3.0, the db4o/Mainsoft port of System.Linq.Expressions from the Mono project after adding the missing Queryable sources, and Matt Warren's IQToolkit on Codeplex to provide a L2S equivalent on the CF.

This is about what it takes, though, since Linq expression trees are not supported on .Net CF 3.5.

I was able to use the DbEntityProvider/DbEntitySession and AttributeMapping/XMLMapping imported to Subsonic from IQToolkit to provide better entity and table-to-class mapping support.

Answer 4

This is one good option generating from dbml file plain POCO classes working with LINQ 2 SQL. Not tested yet but seems promised.

http://www.codeplex.com/ULinqGen